DenseMapInfo.h revision 360784 
1//===- llvm/ADT/DenseMapInfo.h - Type traits for DenseMap -------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file defines DenseMapInfo traits for DenseMap.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_ADT_DENSEMAPINFO_H
14#define LLVM_ADT_DENSEMAPINFO_H
15
16#include "llvm/ADT/ArrayRef.h"
17#include "llvm/ADT/Hashing.h"
18#include "llvm/ADT/StringRef.h"
19#include "llvm/Support/PointerLikeTypeTraits.h"
20#include "llvm/Support/TypeSize.h"
21#include <cassert>
22#include <cstddef>
23#include <cstdint>
24#include <utility>
25
26namespace llvm {
27
28template<typename T>
29struct DenseMapInfo {
30  //static inline T getEmptyKey();
31  //static inline T getTombstoneKey();
32  //static unsigned getHashValue(const T &Val);
33  //static bool isEqual(const T &LHS, const T &RHS);
34};
35
36// Provide DenseMapInfo for all pointers.
37template<typename T>
38struct DenseMapInfo<T*> {
39  static inline T* getEmptyKey() {
40    uintptr_t Val = static_cast<uintptr_t>(-1);
41    Val <<= PointerLikeTypeTraits<T*>::NumLowBitsAvailable;
42    return reinterpret_cast<T*>(Val);
43  }
44
45  static inline T* getTombstoneKey() {
46    uintptr_t Val = static_cast<uintptr_t>(-2);
47    Val <<= PointerLikeTypeTraits<T*>::NumLowBitsAvailable;
48    return reinterpret_cast<T*>(Val);
49  }
50
51  static unsigned getHashValue(const T *PtrVal) {
52    return (unsigned((uintptr_t)PtrVal) >> 4) ^
53           (unsigned((uintptr_t)PtrVal) >> 9);
54  }
55
56  static bool isEqual(const T *LHS, const T *RHS) { return LHS == RHS; }
57};
58
59// Provide DenseMapInfo for chars.
60template<> struct DenseMapInfo<char> {
61  static inline char getEmptyKey() { return ~0; }
62  static inline char getTombstoneKey() { return ~0 - 1; }
63  static unsigned getHashValue(const char& Val) { return Val * 37U; }
64
65  static bool isEqual(const char &LHS, const char &RHS) {
66    return LHS == RHS;
67  }
68};
69
70// Provide DenseMapInfo for unsigned chars.
71template <> struct DenseMapInfo<unsigned char> {
72  static inline unsigned char getEmptyKey() { return ~0; }
73  static inline unsigned char getTombstoneKey() { return ~0 - 1; }
74  static unsigned getHashValue(const unsigned char &Val) { return Val * 37U; }
75
76  static bool isEqual(const unsigned char &LHS, const unsigned char &RHS) {
77    return LHS == RHS;
78  }
79};
80
81// Provide DenseMapInfo for unsigned shorts.
82template <> struct DenseMapInfo<unsigned short> {
83  static inline unsigned short getEmptyKey() { return 0xFFFF; }
84  static inline unsigned short getTombstoneKey() { return 0xFFFF - 1; }
85  static unsigned getHashValue(const unsigned short &Val) { return Val * 37U; }
86
87  static bool isEqual(const unsigned short &LHS, const unsigned short &RHS) {
88    return LHS == RHS;
89  }
90};
91
92// Provide DenseMapInfo for unsigned ints.
93template<> struct DenseMapInfo<unsigned> {
94  static inline unsigned getEmptyKey() { return ~0U; }
95  static inline unsigned getTombstoneKey() { return ~0U - 1; }
96  static unsigned getHashValue(const unsigned& Val) { return Val * 37U; }
97
98  static bool isEqual(const unsigned& LHS, const unsigned& RHS) {
99    return LHS == RHS;
100  }
101};
102
103// Provide DenseMapInfo for unsigned longs.
104template<> struct DenseMapInfo<unsigned long> {
105  static inline unsigned long getEmptyKey() { return ~0UL; }
106  static inline unsigned long getTombstoneKey() { return ~0UL - 1L; }
107
108  static unsigned getHashValue(const unsigned long& Val) {
109    return (unsigned)(Val * 37UL);
110  }
111
112  static bool isEqual(const unsigned long& LHS, const unsigned long& RHS) {
113    return LHS == RHS;
114  }
115};
116
117// Provide DenseMapInfo for unsigned long longs.
118template<> struct DenseMapInfo<unsigned long long> {
119  static inline unsigned long long getEmptyKey() { return ~0ULL; }
120  static inline unsigned long long getTombstoneKey() { return ~0ULL - 1ULL; }
121
122  static unsigned getHashValue(const unsigned long long& Val) {
123    return (unsigned)(Val * 37ULL);
124  }
125
126  static bool isEqual(const unsigned long long& LHS,
127                      const unsigned long long& RHS) {
128    return LHS == RHS;
129  }
130};
131
132// Provide DenseMapInfo for shorts.
133template <> struct DenseMapInfo<short> {
134  static inline short getEmptyKey() { return 0x7FFF; }
135  static inline short getTombstoneKey() { return -0x7FFF - 1; }
136  static unsigned getHashValue(const short &Val) { return Val * 37U; }
137  static bool isEqual(const short &LHS, const short &RHS) { return LHS == RHS; }
138};
139
140// Provide DenseMapInfo for ints.
141template<> struct DenseMapInfo<int> {
142  static inline int getEmptyKey() { return 0x7fffffff; }
143  static inline int getTombstoneKey() { return -0x7fffffff - 1; }
144  static unsigned getHashValue(const int& Val) { return (unsigned)(Val * 37U); }
145
146  static bool isEqual(const int& LHS, const int& RHS) {
147    return LHS == RHS;
148  }
149};
150
151// Provide DenseMapInfo for longs.
152template<> struct DenseMapInfo<long> {
153  static inline long getEmptyKey() {
154    return (1UL << (sizeof(long) * 8 - 1)) - 1UL;
155  }
156
157  static inline long getTombstoneKey() { return getEmptyKey() - 1L; }
158
159  static unsigned getHashValue(const long& Val) {
160    return (unsigned)(Val * 37UL);
161  }
162
163  static bool isEqual(const long& LHS, const long& RHS) {
164    return LHS == RHS;
165  }
166};
167
168// Provide DenseMapInfo for long longs.
169template<> struct DenseMapInfo<long long> {
170  static inline long long getEmptyKey() { return 0x7fffffffffffffffLL; }
171  static inline long long getTombstoneKey() { return -0x7fffffffffffffffLL-1; }
172
173  static unsigned getHashValue(const long long& Val) {
174    return (unsigned)(Val * 37ULL);
175  }
176
177  static bool isEqual(const long long& LHS,
178                      const long long& RHS) {
179    return LHS == RHS;
180  }
181};
182
183// Provide DenseMapInfo for all pairs whose members have info.
184template<typename T, typename U>
185struct DenseMapInfo<std::pair<T, U>> {
186  using Pair = std::pair<T, U>;
187  using FirstInfo = DenseMapInfo<T>;
188  using SecondInfo = DenseMapInfo<U>;
189
190  static inline Pair getEmptyKey() {
191    return std::make_pair(FirstInfo::getEmptyKey(),
192                          SecondInfo::getEmptyKey());
193  }
194
195  static inline Pair getTombstoneKey() {
196    return std::make_pair(FirstInfo::getTombstoneKey(),
197                          SecondInfo::getTombstoneKey());
198  }
199
200  static unsigned getHashValue(const Pair& PairVal) {
201    uint64_t key = (uint64_t)FirstInfo::getHashValue(PairVal.first) << 32
202          | (uint64_t)SecondInfo::getHashValue(PairVal.second);
203    key += ~(key << 32);
204    key ^= (key >> 22);
205    key += ~(key << 13);
206    key ^= (key >> 8);
207    key += (key << 3);
208    key ^= (key >> 15);
209    key += ~(key << 27);
210    key ^= (key >> 31);
211    return (unsigned)key;
212  }
213
214  static bool isEqual(const Pair &LHS, const Pair &RHS) {
215    return FirstInfo::isEqual(LHS.first, RHS.first) &&
216           SecondInfo::isEqual(LHS.second, RHS.second);
217  }
218};
219
220// Provide DenseMapInfo for StringRefs.
221template <> struct DenseMapInfo<StringRef> {
222  static inline StringRef getEmptyKey() {
223    return StringRef(reinterpret_cast<const char *>(~static_cast<uintptr_t>(0)),
224                     0);
225  }
226
227  static inline StringRef getTombstoneKey() {
228    return StringRef(reinterpret_cast<const char *>(~static_cast<uintptr_t>(1)),
229                     0);
230  }
231
232  static unsigned getHashValue(StringRef Val) {
233    assert(Val.data() != getEmptyKey().data() && "Cannot hash the empty key!");
234    assert(Val.data() != getTombstoneKey().data() &&
235           "Cannot hash the tombstone key!");
236    return (unsigned)(hash_value(Val));
237  }
238
239  static bool isEqual(StringRef LHS, StringRef RHS) {
240    if (RHS.data() == getEmptyKey().data())
241      return LHS.data() == getEmptyKey().data();
242    if (RHS.data() == getTombstoneKey().data())
243      return LHS.data() == getTombstoneKey().data();
244    return LHS == RHS;
245  }
246};
247
248// Provide DenseMapInfo for ArrayRefs.
249template <typename T> struct DenseMapInfo<ArrayRef<T>> {
250  static inline ArrayRef<T> getEmptyKey() {
251    return ArrayRef<T>(reinterpret_cast<const T *>(~static_cast<uintptr_t>(0)),
252                       size_t(0));
253  }
254
255  static inline ArrayRef<T> getTombstoneKey() {
256    return ArrayRef<T>(reinterpret_cast<const T *>(~static_cast<uintptr_t>(1)),
257                       size_t(0));
258  }
259
260  static unsigned getHashValue(ArrayRef<T> Val) {
261    assert(Val.data() != getEmptyKey().data() && "Cannot hash the empty key!");
262    assert(Val.data() != getTombstoneKey().data() &&
263           "Cannot hash the tombstone key!");
264    return (unsigned)(hash_value(Val));
265  }
266
267  static bool isEqual(ArrayRef<T> LHS, ArrayRef<T> RHS) {
268    if (RHS.data() == getEmptyKey().data())
269      return LHS.data() == getEmptyKey().data();
270    if (RHS.data() == getTombstoneKey().data())
271      return LHS.data() == getTombstoneKey().data();
272    return LHS == RHS;
273  }
274};
275
276template <> struct DenseMapInfo<hash_code> {
277  static inline hash_code getEmptyKey() { return hash_code(-1); }
278  static inline hash_code getTombstoneKey() { return hash_code(-2); }
279  static unsigned getHashValue(hash_code val) { return val; }
280  static bool isEqual(hash_code LHS, hash_code RHS) { return LHS == RHS; }
281};
282
283template <> struct DenseMapInfo<ElementCount> {
284  static inline ElementCount getEmptyKey() { return {~0U, true}; }
285  static inline ElementCount getTombstoneKey() { return {~0U - 1, false}; }
286  static unsigned getHashValue(const ElementCount& EltCnt) {
287    if (EltCnt.Scalable)
288      return (EltCnt.Min * 37U) - 1U;
289
290    return EltCnt.Min * 37U;
291  }
292
293  static bool isEqual(const ElementCount& LHS, const ElementCount& RHS) {
294    return LHS == RHS;
295  }
296};
297
298} // end namespace llvm
299
300#endif // LLVM_ADT_DENSEMAPINFO_H
301